ogy, organizational skills and know-how, and a willingness to work round the clock.

Even with these advantages, the odds of finding Tenacious were never good. On February 16, 2007, in consultation with the Coast Guard and Gray’s family, the team agreed to call off the search. Tenacious remains lost to this day, despite a subsequent extensive underwater search of the San Francisco coastline. 4

Gray was famous for many things, including his determination to work with practitioners to transform the practical challenges they faced into scientific questions that could be formalized and addressed by the research community. As the search for Tenacious wound down, a number of us felt that even though the effort was not successful on its own terms, it offered a Jim-Gray-like opportunity to convert the particulars of the experience into higher-level technical observations of more general interest. One goal was to encourage efforts to “ democratize” the ability of families and friends to use technology to assist SAR, so people whose social network is not as well-connected as Gray’s could undertake analogous efforts. In addition, we hoped to review the techniques we used and ask how to improve them further to make the next search effort more effective. To that end, in May 2008, the day after a public tribute to Gray at the University of California, Berkeley, we convened a meeting of search participants, including the Coast Guard. This was the first opportunity for the virtual organization that had searched for Tenacious to meet face-to-face and compare stories and perspectives.

One sober conclusion the group
quickly reached was that its specific
lessons on maritime SAR could have
only modest impact, as we detail here.
However, we still felt it would be con-
structive to cull lessons learned and
identify technical challenges. First,
maritime search is not a solved prob-
lem, and even though the number of
lives to be saved is small, each life is
precious. Second, history shows that
technologies developed in one applica-
tion setting often have greater impact
in others. We were hopeful that les-
sons learned searching for Gray could
inform efforts launched during larger
life-threatening scenarios, including
civilian-driven efforts toward disas-
ter response and SAR during natural
disasters and military conflict. More-
over, as part of the meeting, we also
brainstormed about the challenges of
safety and prevention.

Background

The amateur effort to find Tenacious and its skipper began with optimism but little context as to the task at hand. We had no awareness of SAR practice and technology, and only a vague sense of the special resources Gray’s friends could bring to bear on a problem. With the benefit of hindsight, we provide a backdrop for our discussion of computer science challenges in SAR, reflecting first on the unique character of the search for Tenacious, then on the basics of maritime SAR as practiced today.

Tenacious SAR. The search for Te-
nacious was in some ways unique and
in others a typical volunteer SAR. The
uniqueness had its roots in Gray’s
persona. In addition to being a singu-
lar scientist and engineer, he was dis-
tinctly social, cultivating friendships
and collaborations across industries
and sciences. The social network he
built over decades brought enormous
advantages to many aspects of the
search, in ways that would be very dif-
ficult to replicate. First, the team that
assembled to find Tenacious included
leaders in such diverse areas as com-
puting, astronomy, oceanography, and
business management. Second, due
to Gray’s many contacts in the busi-
ness and scientific worlds, funds and
resources were essentially unlimited,
including planes, pilots, satellite im-
agery, and control of well-provisioned
computing resources. Finally, the story
of famous-scientist-gone-missing at-
tracted significant media interest, pro-
viding public awareness that attracted
help with manual image analysis and
information on sightings of debris and
wreckage.